A loudspeaker, also called speaker, is an acoustic transducer which can transform electronic signal into sound wave and be transmitted. Loudspeaker is a common device which is often incorporated in most electronic devices for outputting sound. Sizes of loudspeaker are variable, from a small size for use of earphone, headset or mobile phone to a super size for use of music concerts or movie theaters, giving the loudspeaker a wide range of application.
A conventional loudspeaker usually consists of a frame; and a U-yoke is secured directly on the bottom thereof. Inside the frame, a magnet, a washer, a voice coil and a dust cap are arranged following such order; and a diaphragm is coupled with the upper edge of the frame and a spider usually set on the bottom of the diaphragm. With opening of the diaphragm facing upwardly as a shape of a funnel, said configuration of the traditional loudspeaker may produce distortion and reduce the quality of the sound.
Moreover, said configuration limits the size of loudspeaker and produces higher friction which degrades the quality of the sound, and higher cost for manufacture; the application range of the speaker is therefore reduced.